The FLOATING PLATFORM is a modular construction, which is intended to
function as a buoyant foundation for N55 SPACEFRAME (see manual for N55
SPACEFRAME), or for other lightweight constructions. It can also be used
for other purposes, for example building land.
The FLOATING PLATFORM is a space lattice, comprised of small modules made
from stainless steel with built-in buoyant tanks. The small modules in the
platform can all be assembled by hand. The modular system facilitates gradual
extensions and makes the platform less vulnerable to damage; for example,
leaks only have local impact and can be repaired locally. The platform draws
approximately 1.2 meters when loaded.

Technical background:

Floating systems that lie still in the water most of the time have other
requirements than ships and barges that have to be stable during navigation.
For example, stability can be obtained without ballasting, thereby reducing
the use of materials. In addition, construction methods that normally are
not used on water can be applied.
The floating system can also be shaped according to the intended usage.
The FLOATING PLATFORM has comparatively low net buoyancy. This is an economic
advantage, but limits the amount of weight that can be added to the platform.
However, the modularity of the platform offers the possibility to add more
buoyancy when there is a need for it: extra tanks may be connected to the
sides of the platform, material may be put into the cavities in the steel
truss or extensions can be made from the same building system. Tanks for
water and wastewater, toilets etc. can be integrated in ways that do not
add load to the construction.

Construction:

The platform is constructed as an "octet truss" space lattice
(see Manual for N55 SPACEFRAME) and is shaped as an equilateral triangle.
189 polyethylene tanks make the platform buoyant. They are concentrated
in the three pontoons situated in each corner of the platform. The pontoons
are constructed from 3 layers of tanks and are shaped as tetrahedra with
one vertex pointing downwards and a plane facing upwards.

Buoyancy: The tanks are
made from low-density polyethylene. They are built into tetrahedra
of stainless, acid-resistant steel, which are assembled into a coherent
"octet truss" space lattice. The buoyancy of the tanks
is reduced at low temperatures because they are made of flexible
material (there is an approximated 10% difference between 0°
and 20° C).

Due to the stronger buoyancy in the pontoons, leverage creates a strain
towards the centre. This is compensated for by reinforcing the platform
with a sidepiece consisting of an extra layer of struts.
The cavities between the tanks in the steel truss create turbulence, and
thus the effect of the waves is reduced when they meet the platform. The
triangular shape also adds stability as the platform floats on three "points".
Boards are attached to the steel truss and plates of birch plywood are fastened
on top of them. The plywood functions both as a deck and a floor. It also
contributes to the stabilisation of the lattice construction. The top construction
is fixed directly onto the wood as well as with bolts through the wood to
the platform.
The space lattice in the platform is constructed from a steel type that
is the most durable in brackish water, on the condition that plants and
algae will grow on it. However, galvanic currents will cause sporadic corrosion
on the steel unless measures are taken. Zinc blocs are attached to the steel
with a distance of 1 meter maximum. Zinc is a more reactive metal than stainless
steel and will therefore provide sacrificial protection. Using this method,
one should be able to avoid any corrosion of the steel.

Wind load and mooring:

The construction as a whole is stable and safe in heavy weather and wind
up to the strength of a hurricane, provided that it is well moored. The
maximum load on the large sides is 3000 kg horizontally and 300 kg vertically
in a wind of 33 m/s (i.e. hurricane conditions). To secure the construction
under these conditions, it should be moored from each corner with a strength
of 3.3 tons and an angle of 12°.
There are mooring chains fixed around 2 of the node points in each corner
of the platform. Two bruce-anchors hold one of the corners and the other
two are moored to bollards on land.

The tanks are concentrated in the corners of the platform.

Extensions:

In order to increase the buoyancy it is possible to attach extra tanks.
The tanks can also be used for wastewater, sewage and other purposes.

Maintenance:

Neither the steel nor the tanks are treated: they need no other maintenance
than regular checking. The construction can be lifted up in order to check
thoroughly for corrosion and leaks.
The zinc blocs must be exchanged when the zinc is gone. The plywood deck
must be checked regularly for damage, and the damp seal on the edges must
be maintained.

Assembling the FLOATING PLATFORM at FACTORY.

Boards of birch plywood
are fixed with bolts to the node points of the construction. The
boards are treated against dampness with epoxy and light primer.

The top construction is
fixed directly onto the wood as well as with bolts through the wood
to the platform